A survey of background and prior art in the fields of this invention reveals the following. Stimson and Dowell in U.S. Pat. No. 3,934,686 teach carbon disk brakes with keyway formations reinforced by filament carbon inserts. Zarembka in U.S. Pat. No. 4,187,932 discloses the use of pyrolyzed carbon-containing ribbon wrapped radially around a brake disk core. Resin is then added, and the assembly pyrolyzed to obtain an integral brake disk. Wiseman and Kovac in U.S. Pat. No. 4,286,694 present brake disks of carbon or other porous material which contain grooves on opposing surfaces so as to vent steam or other gases generated during braking. Bauer in U.S. Pat. No. 4,291,794 reveals the use of various mixtures of pyrolytic carbon and graphite assemblies and also cross-hatched grooves in such assemblies for power transmission clutches. Taylor in U.S. Pat. No. 4,297,307 discloses means for assemblying carbon-carbon fiber composites used for aircraft bake disks. Chareire in U.S. Pat. No. 4,457,967 reveals brake disks utilizing carbon-carbon composite materials with carbon fibers of different lengths oriented in different directions relative to the plane of the disks. Winckler in U.S. Pat. No. 4,700,823 teaches the use of carbon vapor deposition (CVD) in preparing oil lubricated clutch assemblies. Fox and East in U.S. Pat. No. 4,778,548 teach bonding woven carbon fabric friction materials in which the tendency of bonding adhesives to bleed through the pores of the friction material are reduced. Tilton and Sorce in U.S. Pat. No. 4,846,326 present a friction clutch which allows uniform distribution of friction loads over carbon plates. Guichard in U.S. Pat. No. 4,890,700 reveals carbon disk brake rotors fitted with reinforcing riders which fit into trapezoidal-shaped drive notches around the periphery of such rotors. Seiz and Eldridge in U.S. Pat. No. 5,083,650 teach an automated process for making friction material having heat-resistant paper support bearing resin-bonded carbon particles. Bommier and Chareire in U.S. Pat. No. 5,242,746 disclose various friction elements of composite carbon-carbon materials and differential textures. Prud'Homme in U.S. Pat. No. 5,325,948 presents a clutch with structural carbon-carbon friction plates. Chareire and Salem in U.S. Pat. No. 5,405,650 reveal a process for producing carbon-carbon brake disks with holes arranged in it to allow better CVD compregnation. Bernal, Hendrix, and Tilton in U.S. Pat. No. 5,415,262 disclose a carbon to carbon friction mechanism
Carbon-fiber cloth is made by mixing powdered carbon with poly-acrylyl-nitrile (PAN), a liquid polymer. This mixture is made into fiber. The fiber is woven into cloth. The cloth is the heated to about 1000 degrees C. for a few hours. All of the organic material burns up, leaving pure carbon-fiber cloth.
Stitching carbon-fiber cloth doesn't compress it as much as does hot pressing it. This is important because hot pressing carbon-fiber cloth results in a lower fiber volume of fraction materials made from the cloth. The cloth can then be built up with carbon vapor deposition (CVD) which is thought to be an advantageous form of carbon use in friction surfaces. However, stitching carbon fiber cloth is thought to be advantageous in the following manner: The carbon-fiber used to stitch layer of friction materials together is generally oriented perpendicular to the outer exposed friction surface which allows said fibers to conduct heat away from the exposed friction surface for better wear.
As currently practiced in the art, a typical disk will have an inner diameter (ID) of 4.175 inches and a outer diameter (OD) of 4.98 inches. Typical disks can be made of "papers" composed of randomly oriented resin binder, KEVLAR polymeric fiber, reycled materials, and filler. Disks can also be made of woven (i.e. nonrandomly oriented) carbon-carbon fiber cloth (as for example in Eaton/Hitco disks) described previously.
But "papers" and carbon-carbon fiber cloth are expensive and suffer from a very low materials utilization rate. That is, there is high waste of sheet or cloth materials as currently utilized in art field of friction disk fabrication. For example, if 1-ply rings with ID of 4.175 in. and OD of 4.98 in. are cut from a rectangular sheet, it can be calculated that there will be a 73% waste of material. In the automotive transmission industry, friction paper waste can be as high as 80%-90%.